Cycle timer



F'. A. PEARSON May 3; 1949.

CYCLE TIMER 3 Sheets-Sheet 1 Filed June 9, 1944 Fjg. i

INVENTOR. IZ'A. PEARSON May 3, 1949.

Filed June 9, 1944 F. A. PEARSON CYCLE TIMER 3 Sheets-Sheet 2 7LNVENTOR.

EA. PEARSON ATTORNEY.

May 3, 1949. F. A. PEARSON CYCLE TIMER Filed June 9, 1944 3 Sheets-Sheet3 INVENTUR EA. PEARSO/f ATTURNEY.

I ating mechanism for a timer.

Patented May 3, 1949 crops TIMER Frank Arthur Pearson, Moline, IiL,assignor to Eagle Signal Corporation, Moline, 111., a corporation ofMassachusetts Application June 9, 1944, Serial No. 539,580

8 Claims. (Cl. 181- 1) The present invention relates to a cycle timer,designed particularly for use in connection .with washing apparatus, thesame being provided with means for adjusting the length of the period ofsoaking the clothing. Cycle timers for use in connection with clotheswashing machines are already known but, so far as I am aware, they areall designed to operate a fixed period of time for each operation whichis timed. By contrast therewith, mine provides for the adjustment of the"soak period, which is desirable since some clothing requires a shorterperiod of soaking and other clothing requires a longer period: This,then, is the primary object of my invention. Another object is theprovision of an improved oper- This invention comprises, also, suchfurther objects, advantages, and capabilities as will latermore fullyappear and as are inherent in the structure disclosed herein. Myinvention further resides in the combination, construction, andarrangement of parts illustrated in the accompanying drawings and, whileI have shown therein what is now regarded .as the preferred embodimentof this invention, I desire the same to be understood as illustrativeonly and not to be interpreted in a limiting sense.

In the drawings annexed hereto and forming a part hereof,

Fig. 1 is a front view of my timer showing the dial for use inregulating the soak" period;

Fig. 2 is a plan view looking down on the structure shown in Fig. 1;

Fig. 3 represents a transverse section'substantially along the planeindicated by the line 3--3, Fig. 2; I

Fig. 4 represents a transverse section along the plane indicated by theline 4-4, Fig. 2;

Fig. 5 represents a transverse section substantially along the planeindicated by the line 5--5, Fig. 2;

Fig. 6 represents a transverse section'substantially along the planeindicated by the line 6-5, Fig. 2;

Fig. 7 is an expanded perspective view of parts of the operatingmechanism; and

Fig. 8 is a fragmentary showing of parts of the operating mechanism,shown in longitudinal section.

This construction is provided with a synchronous motor I and a faceplate 2 in front of which is a combined operating knob and indicatingpointer 3, used to start the operation of the machine and set theoperating parts of the mechanism so that the soaking period will be inaccordance with the desires of the person using 2 the machine. On theface plate is a dial 4 having at one end the letter S and along an edgethereof the numerals II, IS, IS, and 23. Of these, the letter Sindicates start and the numerals indicate the number of minutes ofsoaking which the operatordesires that the clothes shall have.

By referring to Figs. 2 and 7, it will be seen that there are severalratchets 5, 6, 'l, and 8, and cams 9, ill, ll, l2, I3, and i4.Associated with each of the cams, 9 to i 4, inclusive, is a switch,these being designated by the numerals [5 to 20. inclusive. Each switchhas a connector 2| connected thereto for attachment of circuit wiresleading to the apparatus to be controlled, except that from switch I! awire no leads to the motor I. Below the switches is a bus-bar 22 havingcontact elements thereon to cooperate with corresponding contactelements of the switches. The bus-bar 22 is mounted, by means of arms23, upon the insulating block or bar 24, supported at one end by a frontplate 25 which is just inside of the face plate 2 and, at its secondend, by a back plate 26. The plates 25 and 26 are connected by posts 21and the insulating bar 24. It is appropriate to remark that the order ofarrangement of the cams 9 to l4, inclusive, and their correspondingswitches is immaterial, it being important only that the appropriateconnections are made to the connectors 2i.

The power line connectors 28 and. 28:: are provided for connecting thistimer to a power circuit. Back of the back plate 23 is a housing 29 inwhich are mounted the gearswhich transmit rotation from the drive shaftof the motor I to the cam shaft 30 by means of which the cam 3| issupported and rotated.

Referring now to Fig. 7, it will be seen that which is designed to'givethe relationship between the cam H and the ratchets 1 and 8. Se-

- cured to the underside of the insulating block 24 is a double pawl 32,having two arms 32a and 32b, the former bearing against the ratchet 8and the latter against the ratchets 6 and 1. Another pawl 33 is alsosecured to the insulating block 24 with the pawl 32, as indicated at 34,the pawl 33 underlying the pawl 32 and being secured to the insulatingblock 24 by the same screws which pass through the pawl 32 and into theblock. It should be remarked that the pawl arm 32b can contact theratchet 6 only when it drops into the notches 1a and 1b on the edge ofcam 1. Because of the separation of the ratches 6 and l, in Fig.

i 1, it has been necessary to duplicate the showing of the pawl arm 32b.However, it should be understood that this is merely a double showing ofthe same element, designed to give a conception of its relation to theother elements.

A bell crank lever II, pivotally mounted on the shaft II, is locatedbetween the ratchets I and 6. At one end, this has a finger II bent at aright angle to the plane of the body of the lever, this finger extendinginto the path of the cam II and riding on the edge thereof. It istherefore apparent that, as the motor I causes rotation of the shaft II,the lever II will be actuated in one direction by the cam II. The end IIof the lever II has a spring- II secured thereto for moving the lever inthe opposite direction from that caused by the cam II. As shown in Figs.3 and 6, the second end of the spring II is connected to a post 21.

A second finger II is bent laterally from the lever II and serves assupporting mean for the double pawl 4i, having the pawl arms Ma and 4ibwhich normally engage the ratchets I and I. As the lever II is rockedbythe cam II, the pawl arm 4la moves back one notch along the edge of theratchet I. Then as the cam II releases the lever 35 and the latter ismoved forward by the spring 39, the pawl arm 4| 0 moves the ratchet Ione step forward, advancing the shaft 42 correspondingly. As the ratchetis advanced, the nose of the pawl arm I2a drops into a notch in ratchet8 and holds the ratchet against retrograde movement with the pawl armIla, upon its next backward movement. It is therefore clear that theshaft 42 moves forwardly with a small step by step motion until itscycle is completed. This shaft 42 has a reduced extension 42a whichextends through ratchet I and into a longitudinal opening in shaft II tofurnish a bearing for the forward end of the shaft 42. As indicated at43, one tooth'of the ratchet I is omitted. Therefore, when the pawl arma reaches this point, it is unable to advance the ratchet.

A spring 4I, having a re-curved end 46, is mounted on the underside ofbar or block 24, with the pawls 32 and II, and is held in place thereonby the same screws which hold the pawls in place. The inner end of thisspring bears upon the arm 41a of pawl 4! to provide means for wedgingarm Ila into engagement with ratchet I, thus to prevent overtravel ofshaft I2 and associated parts beyond the point to which it is advancedby cam 3i. Pawl II engages in the notches of ratchet I to preventbackward rotation thereof when arm 32a engages in notch 4I.

Normally, the ratchet 1 holds the pawl arms 4lb and I2b out ofengagement with the edge of ratchet I as the latter is moved forward bythe pawl arm 4la engaging ratchet I, as the lever II oscillates. Whenratchet I has rotated so notch lb is presented to the end of pawl 4lb,the pawl engages the teeth in ratchet I. Since ratchet I is free torotate on shaft 42a with nothing preventing its backward movement,succeeding oscillations of pawl 4 lb merely rotate ratchet i forward andbackward while ratchet I and shaft 42 continue their step-by-stepforward advance. When ratchet i has advanced far enough to allow pawlarm 32b to fall into notch lb at point 1d, pawl arm 32b engages theteeth in ratchet I. Now, as pawl arm 4 lb oscillates, being inengagement with ratchet I, it moves that ratchet forward one notch at atime, backward movement of the ratchet 6 being prevented by pawl arm32b. The shoulder is of ratchet I does not extend out wardly far enough,radially, to release the pawl 4 arms 32b or 4") from the notches ofratchet I. but when the edge 1e, which extends a greater distance,radially, irom the shaft 42, comes under the pawl arms 4| b and I, thepawls are raised to release the ratchet I which snaps back against pin41 under the influence f spring Ia secured at one end to pin 41 and atits other end to a hub on ratchet I.

As shown in Fig. 7, the pin 41 is carried by the ratchet I and extendsthrough a notch in the edge of the ratchet I. Since ratchet I is securedrigidly to shaft II on which the knob I is mounted. turning this knobturns ratchet I and causes a partial revolution of pin 41 about the axisof shaft II. A stop member or pawl II, pivotally mounted on one of theposts 21. has a finger II bent perpendicularly with relation to theplane of the stop member and extending back away from the front plate25. The ratchet I is provided along its marginal edge with notches to beengaged by the finger 49 so that the ratchet will be held reasonablyfirmly in adjusted position. However, it can be moved without dimcultyby turning the knob I. At one corner of the ratchet I there is a stopfinger II which engages the projection or finger 49 when the knob I isturned in a counterclockwise direction to the limit of its motion, thatis, to the index line marked 23 on the dial. When the indicator on thedial reaches this line, stop finger 50 engages projection 4! andprevents further rotation.

As shown in Fig. 4, pawl 4I is pivoted on the lower post 21 and isactuated into holding position by a spring I2 which, at its second end,is se cured to the outer end of a lever II, pivoted on a hub surroundingand constituting a part of shaft 36 and substantially filling theopening in the lever II. The springbiased movement of lever 48 islimited by projection 4I engaging ratchet I and the spring biasedmovement of lever II is limited by pin IIa.

Bent at a right angle to the plane of the lever II is an arm upon whichis rigidly mounted a spring pawl I4, constructed and arranged to ensa ethe shoulder 1d of the ratchet I. When the hump II on the cam II isunder the switch element IT, as shown in Figs. 4 and 7, the apparatus isin ofP' position, that is, the current is cut of! from the motorcircuit, including the wires Fla and "b. The wire l'lb has a terminalilc which is connected by a screw to bar 24 and to a terminal 28, andthe other motor wire "a is connected to contact finger H. One of thepower line wires (not shown) is connected to terminal 2! and the otherpower line (not shown) is connected to terminal 2Ia which, in turn, isconnected to bus bar 22. Terminals 2i and He are insulated by theinsulating bar 24 from bus bar 22. Thus the motor circuit can be tracedfrom one power line through terminal 2I, terminal IIc, wire lib, thecoil in motor I, wire lla, contact finger I'I, bus bar 22, terminal II,and the other power line Therefore, when contact i1 is closed on bus bar22, the motor runs, and when it is raised away from 22, the motor stops.The lead wires Na and Nb lead through the back plate 2I and into themotor case of the motor I.

When it is desired to start the mechanism into operation, hump II, beingunder contact member H, the knob I is turned in a clockwise direction tothe indicating line B and then it is permitted to return to the line H.Turning this knob in a clockwise direction to the 8 position causes thefinger II to engage the finger II on lever 83 and turn the latter aroundthe shaft ll. This causes pawl ll to move forwardly and engage theshoulder Id of ratchet I, rotating the shaft l2 and the cams l to il. Inorder to insure that the pawl Bl will not miss the shoulder Id, when thelatter is in proper position to be engaged, a spring arm 51 on fingerlil projects into the path of the forwardly moving pawl Il and pressesit inwardly into engagement with the shoulder Id.

When knob 3 is turned clockwise to the S position, stop finger 58contacts projection on lever 48 to prevent knob 3 being turned beyondthe S position. Since the radius of cam I at Ic is less than the radiusof cam I at Id, pawl ll will engage only shoulder Id. Therefore, aftershaft l2a, ratchet I, and other associated parts are advanced to the Sposition, knob 8 is ineffective to again advance the shaft lla until ithas completed its revolution.

Inasmuch as the cams 9, iii, and i: to II, inclusive, may be very muchmodified for controlling the circuits to the working apparatus,according to the desire of the manufacturer, and, since these do notconstitute a part of the present invention, they are not disclosed indetail, being disclosed in part only in Figs. 4 and 5. However, when theknob 8 is turned to the starting position and allowed to come back tothe line ii, the apparatus will be set for a soaking period of elevenminutes. If, on the other hand, it is desired that the clothes soak forsixteen minutes,

let us say, then the knob is turned to the left, to a the lineindicating sixteen (16) minutes, immediately after the motor is startedinto operation. the knob 3 being allowed to rest there. This will causethe soaking period to be extended from eleven (11) minutes to sixteen(16) minutes. After the soaking period has been completed, the apparatuswill go on with the next step in the cycle of operation.

Operation When it is desired to start the washing operation, theoperator turns the knob 3 to the S position and then releases it. Thisknob then returns to the position indicated by the numeral ii on thedial l. If the operator wishes a longer soak time, he or she turns theknob to the desired position on the dial. The timer then completes itscycle and stops.

More specifically, with the timer in the oil position and with cam iiholding motor contact i1 open, ratchet l is in a position such thatshoulder 1d occupies the position indicated in Figs. 6 and 7. Now, asthe knob 3 is turned toward the S position, finger ll on ratchet 8,which is connected to knob I, is rotated to engage finger '56 on lever53. Continued rotation of knob 3 now rotates ratchet 5 and lever Itforward. As pawl El attached to lever 58 moves forward, it engagesspring arm 51. The end of pawl 5l is so formed that continued movementof pawl bl when sliding under spring arm 51 forces the end of pawl lldownward into engagement with shoulder Id. Ratchet I with shaft l2 andassociated parts are now moved forward with knob 3. When knob 3 reachesvposition S on the dial, the shaft l2 has advanced one position. Finger58 on ratchet 5 engages the end 09 of lever l8, preventing furtherforward movement of knob 3. When the operator releases knob 3, spring 52returns lever 53 to engage pin 53a. Finger 56, still i being inengagement with finger 50, also returns ratchet 5 and knob 3. Knob 3stops in the position indicated by the numeral i I on the dial whenreturn movement of lever It is stopped by pin "a. Advancing shaft l2 oneposition causes the hump ll on cam ii to move from under contact fingerII, allowing it to close on bus bar 22 and thus close the circuit tostart motor i.

It is pointed out that pawl-Bl is effective to engage only shoulder Idof ratchet I since shoulder 1c of ratchet I is closer to the center thanId. Therefore, after the shaft l2 is once advanced to the startposition, knob 3 is ineffective to advance the shaft at any time duringthe ensuing cycle. This makes it impossible for the operator to shortenany of the intervals of the normal cycle, so proper timing ofeachlnterval of the washing cycle is insured. The normal or minimum soaktime is eleven (11) minutes, as indicated by the position to which theknob I automatically returns. With the motor now running, cam ll isrotated l R. P. M. to actuate bell-crank lever S5 in a counterclockwisedirection, as viewed in Fig. 7. Then, spring 30, connected to lever ll,causes it to turn in the opposite direction with a rapid motion whenlever 3! falls off the high point of cam II. This actuates pawl l i,causing step-by-step rotation of ratchet 8 and forward advancement ofcams l and il, inclusive. These, by operation of the various switchelements I! to 20, open and close the various operating electricalcircuits .with a snap action and control the functioning of themechanisms intended to be controlled by this timer. It should be notedthat in Fig. 'I the pawl arms lia and lib are shown in two differentpositionsin order to show the relations to other elements of thestructure.

Since cam 3i rotates 1 R. RM. to advance the shaft l2 one position perminute, at the end of ten (10) minutes, ratchet 8 will have advanced sothat the cut-away portion l3 of ratchet I will be under pawl arm lia.Shoulder jIc on ratchet I is advanced under the end of pawl arm lib atthe end of the 10th minute, simultaneously with advancement of thecut-away tooth l3. If the soak time is not to be extended beyond eleven(11) minutes, the pawl arm lib engages shoulder I0 and advances shaft l2one position on the next oscillation at the end of the 11th minute. Pawlarm l in then re-engages the teeth of ratchet I to complete therevolution 01 shaft l2 in the regular manner.

If the soak time is to be extended beyond eleven (11) minutes, pawl armlib is held out of engagement with shoulder 10 by the teeth in ratcheti. There is nothing to advance shaft l2 farther since pawl arm li amerely oscillates in notch ll. However, pawl arm lib engages in thenotches of ratchet l and advances this, one notch at a time,

for a period of time corresponding to the increase in the soak periodrepresented by the difference between 11 and the setting of theindicating pointer on knob I. Then, pawl arm lib engages shoulder 8b onratchet 6. As shoulder lb is deeper than the teeth of the ratchet, pawlarm lib drops down low enough to engage, also, shoulder Ic on ratchet I.The next oscillation of pawl arm lib again advances ratchet I and shaftl2. Pawl arm l la now re-engages the teeth in ratchet to continue thestep-by-step advance of shaft Now, a cycle of operation will bedescribed in which the normal or minimum soak time is eleven (11)minutes. The knob 3 is turned forward to advance shaft l2 one position.Spring 52 returns knob 3 to the 11-minute position on the dial. Theratchet 6 is so positioned by pin l! on ratchet I that the shoulder 6bof ratchet 6 is under pawl arm lib. The pawl arms lia and lib oscillatein one-minute cycles, being driven by motor i.

After ten oscillations, the wide notch l3 is presented to pawl arm liaso that lia is ineflective to advance ratchet 8. However, shoulder 10,being in line with the wide notch l3, is now presented to pawl arm libwhich is free to engage shoulder 112, since the teeth of ratchet 6 arein advance of the pawl and no longer hold the pawl arm out of engagementwith ratchet 1. Therefore, on the eleventh (11th) oscillation of lid andlib, pawl arm lib engages shoulder 1c and advances shaft 42 oneposition. This terminates the soak time. On the twelfth (12th)oscillation, pawl arm lib again engages the teeth in ratchet l andcontinues to advance the shaft in the normal manner.

Next, we will assume it is desired to operate the timer with the soakperiod extended five minutes, making a total of sixteen (16) minutes.The operator turns the'knob 3 clockwise to the 8 position to advance theshaft l2 one position to start the motor. The knob 3 is then turnedcounterclockwise to the 16-minute position on the dial. Thiscounterclockwise movement of knob 3 turns ratchet 5 and pin llcounterclockwise five notches beyond the point to which it is moved whenspring 52 returns knob 3 to the 11-minute position. Ratchet 6, beingbiased counterclockwise by spring to against pin ll, also movescounterclockwise five additional notches, to remain in engagement withpin l1. Pawl arm lib will now be over the fifth notch of ratchet I,counting clockwise from 6b. However, pawl arm lib will be held out ofengagement with ratchet 6 by the raised surface of ratchet i. As shaftl! is advanced, notch 1b will first be presented to pawl arm lib,allowing the pawl arm lib to fall into engagement with ratchet 6.Ratchet 6 'will then oscillate with pawl arm lib but will not beadvanced. At the end of the tenth (10th) oscillation of pawl arms lidand lib when the wide notch 43 moves under the pawl arm l in, pawl arm32b falls off the shoulder id into notch lb and engages the teeth ofratchet 6. Pawl arm 32b now holds ratchet 6 against retrograde movement.The succeeding oscillations (11 through 15) of pawl arm lib eachadvances ratchet 6 one tooth. On the sixteenth (16th) oscillation, pawlarm lib engages shoulder 6b, as well as shoulder Tc, and advancesratchet 1 together with shaft 42 one notch. Pawl arm lia now engages theteeth in ratchet 8 and the shaft l2 is rotated stepby-step through theremaining portion of the cycle in the normal manner.

It should be stated that the advance of ratchet 6 is stopped when pawlarm lib drops behind shoulder 6b at the end of the notched part ofratchet 6. The pawl arm lib then merely reciprocates along the unnotchedpart of this ratchet until shoulder is raises pawl arms lib and 32b outof engagement with ratchet 6. Then ratchet 6 snaps back under the biasof spring in to its initial position against pin l1.

Expressed in another way, and perhaps more simply, the motor i, throughshaft 30, cam 3i, arm 35, and pawl arms lia and 32a, advances the camshaft 42; the wide notch l3 stops the advancing of the cam shaft by notfurnishing means to be engaged by the pawl arm lia; the ratchet segment6 is advanced from an initial position by the motor acting through thepawl arm lib when cams l and 8 are stopped, after it has moved apredetermined amount, permitting tion, whereupon e cam shaft advancingmeans again takes up the driving of the shaft, the

ratchet segment being returned to its initial position by the spring la.

It is of course understood that, while the description of the extensionor shortening of a period has been specifically applied to the soak"period, it may equally as well be applied to some other period, as, forexample, the "washing period.

It will of course-be understood that the specific description ofstructure set forth above may be departed from without departing fromthe spirit of this invention as set forth herein and in the appendedclaims.

Having-now described my invention, I claim: 1. In a timer for aplurality of operating electrical circuits, a movable switch element foreach of said circuits, an operating cam for each of said switchelements, a shaft on which said cams are carried and by which they arerotated in contact with the switch elements, intermittently operatingmeans for rotating said shaft, including pawl and ratchet mechanisms,and means adjustable at will for varying the time interval controlled byone of said switch elements, one of said ratchet mechanisms having atooth omitted whereby to cause temporary discontinuance of thefunctioning of that mechanism.

2. In a timer for a plurality of operating electrical circuits, amovable switch element for each of said circuits, an operating cam foreach of said switch elements, a shaft on which said cams are carried andby which they are rotated in contactwith the switch elements,intermittently operating means for rotating said sh'aft, including pawland ratchet mechanisms, one of the teeth of one of said ratchetmechanisms being omitted, thus allowing actuation for a limited periodof part of the ratchet mechanisms without actuation of the remainderthereof whereby to stop rotation of said shaft for said limited period,and means adjustable at will for varying the time interval controlled byone of said switch elements.

3. In a timer for a plurality of operating electrical circuits, amovable switch element for each of said circuits, an operating cam foreach of said switch elements, a shaft on which said cams are carried andby which they are rotated in contact with the switch elements,intermittently operating means for rotating said shaft, including pawland ratchet mechanisms, one of said ratchet mechanisms having one toothomitted, thus allowing actuation for a limited period of part of theratchet mechanisms without actuation of the remainder thereof whereby tostop rotation of said shaft for said limited period, means adjustable atwill for varying the time interval controlled by one of said switchelements, and means for adjusting the length of the period during whichsaid shaft does not rotate.

"4. In a cycle timer provided with a shaft, a motor, means operated bythe motor for causing advancement of said shaft, a second means forcausing the advancement of said shaft to be stopped when said shaft hasadvanced to a predetermined position, said second means being advancedfrom an initial position by the motor when said first means is stopped,and said second means being operative, after a predetermined movement,to make possible the advancement of said shaft past said predeterminedstopping position, whereupon said first means is again effecengagementof pawl arm lib with shoulder 1c tive to advance said shaft, and springmeans for returning said second means to its initial position.

5. In a cycle timer having a shaft, a motor, oscillating means includingtwo pawls driven by said motor, ratchet means attached to said shaft andadvanced with step-by-step movement by one of said pawls, said ratchetmeans having a tooth removed therefrom whereby said shaft is driven bysaid one pawl to a predetermined position in which said pawl isineffective to advance said shaft, said second pawl being operable toengage said ratchet means to advance said ratchet and shaft in saidpredetermined position, and a second ratchet means effective to holdsaid second pawl out of engagement with said first ratchet means, saidsecond ratchet means being operable to be advanced by said oscillatingmeans to a position ineffective to hold said second pawl out ofengagement, whereupon said second pawl can advance said first ratchetmeans and shaft past said predetermined position and render said firstratchet means effective to again advance said shaft.

6. In a cycle timer having a shaft, a motor, oscillating means includingtwo pawls driven by said motor, ratchet means attached to said shaft andnormally driven by one of said pawls, said ratchet means having a toothremoved therefrom whereby said shaft is driven by said one pawl to apredetermined position where said pawl is ineffective to advance saidshaft, said second pawl bein operable to advance said ratchet and shaft,and means effective to hold said second pawl out of engagement with saidratchet means until said means has advanced a predetermined amount.

7. In a cycle timer provided with a shaft having two ratchet wheelsmounted thereon, a motor, oscillating means including two pawls drivenby said motor, one of said pawls engaging one of said ratchet wheels toadvance said shaft with stepby-step motion, said ratchet wheel having atooth removed therefrom to render said means ineffective to advance saidshaft past the position where the pawl engages the space occasioned byremoval of the tooth, said-second ratchet wheel having a toothpositioned to be normally engaged by said second pawl in the position towhich the shaft is advanced by the first pawl, and means effective toprevent engagement of said second pawl and said second ratchet wheel,said means being movable through a predetermined distance by said motorto a position where said second pawl can engage the second ratchet toadvance the shaft one position, the first pawl then being effective aain to advance said shaft.

8. In a cycle timer provided with a shaft having two ratchet wheelsmounted thereon, a motor, means driven by said motor engaging one ofsaid ratchet wheels to advance said shaft with stepby-step motion, saidratchet wheel having a tooth removed therefrom to render said meansineffective to advance said shaft when said shaft reaches apredetermined position, said second ratchet wheel having a notch wherebysaid means is effective to advance said shaft through said position, anda second means operable to hold said first means out of engagement withsaid second ratchet wheel for a predetermined movement of said secondmeans.

FRANK ARTHUR PEARSON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Great Britain June 9, 1927

